If t - 1 and -t -1, t ∈ R, are the roots of (a + 2) x2 + 2ax - 1 = 0 then complete set of values of 'a' is :
∅
( -∞, ∞)
( - ∞, 0)
( 0, ∞)
−2aa+2 = -2 => a+2 = a
Therefore set of values of a is null , i.e ∅